A Li-ion battery used for electric vehicle mainly includes a positive electrode diaphragm, a negative electrode diaphragm, an insulating film, electrolyte, a mechanical structure and other auxiliary structures. The design of negative and positive diaphragm is a multi-electrode-tab design. The structure of the electrode sheet is mainly a solid-core structure, however, the electrode tab of such a structure may have the problems of diaphragm cracking and diaphragm deformation during use of the battery, meanwhile, during cycling process of the battery, the deformation may also cause that the negative electrode and the positive electrode are not fitted tightly, the interface is poor, the performance is bad etc. For a Li-ion battery processed by coiling, the positive and negative electrode sheets are characterized by long and thin, and the material is soft, which is easily broken during processing, particularly, during the rolling and coiling process of the electrode sheet. Generally, during preparation process of an electrode sheet, firstly, coating a layer of active material at the center of a current collector, leaving uncoated regions at the side edges, preforming die cutting on uncoated regions to generate a multi-electrode-tab structure, then rolling the electrode sheet. However, due to different extensibility of the material region and no-material region, during the sheet pressing or coiling process, a stress concentration region may be generated in the coating region and the electrode tab region, the electrode sheet is easily folded or even broken, leading to damage of the electrode sheet or safety problems.
Aiming at the problems in the prior art, the present application is proposed